Collection of trial serum specimens from patients with ovarian carcinoma, lung carcinoma, melanoma, and Hodgkin's disease as well as suitably matched controls. Usually studies of this sort have a considerable loss to follow-up, but Dr. Feit has largely avoided this problem by hiring a records clerk. In addition, careful screening by the nurse recruiter has yeilded a higher proportion of cooperative patients interested in complying with the two year bimonthly follow-up schedule.